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A134660
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Number of odd coefficients in (1+x+x^2+x^3)^n.
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0
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1, 4, 4, 4, 4, 16, 4, 8, 4, 16, 16, 4, 4, 16, 8, 16, 4, 16, 16, 16, 16, 64, 4, 8, 4, 16, 16, 8, 8, 32, 16, 32, 4, 16, 16, 16, 16, 64, 16, 32, 16, 64, 64, 4, 4, 16, 8, 16, 4, 16, 16, 16, 16, 64, 8, 16, 8, 32, 32, 16, 16, 64, 32, 64, 4, 16, 16, 16, 16, 64, 16, 32, 16, 64, 64, 16, 16, 64
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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COMMENTS
| a(n) = 2^A036555(n)
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LINKS
| S. R. Finch, P. Sebah and Z.-Q. Bai, Odd Entries in Pascal's Trinomial Triangle (arXiv:0802.2654)
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FORMULA
| a(n) = gcd(4^n, C(4n, n)). - Peter Luschny, Nov 08 2011
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MAPLE
| seq(igcd(4^n, binomial(4*n, n)), n=0..77); - Peter Luschny, Nov 08 2011
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MATHEMATICA
| PolynomialMod[(1+x+x^2+x^3)^n, 2] /. x->1
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CROSSREFS
| Cf. A000120, A001316, A008287, A036555, A071053.
Sequence in context: A046109 A107680 A202686 * A132383 A115639 A062732
Adjacent sequences: A134657 A134658 A134659 * A134661 A134662 A134663
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KEYWORD
| nonn
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AUTHOR
| S. R. Finch (Steven.Finch(AT)inria.fr), Jan 25 2008
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